The company was tasked with paying special attention to the building's original details and high-level of craftsmanship, when restoration began in 2012. According to The New York Times, the restoration was necessary thanks to the degradation that occurred to the building throughout the decades.

Jeffrey Murphy, a founding partner of the architecture firm told Fast Company that making repairs and updates, without compromising the cathedral's historical materials, was not without its challenges.

"In some ways it's daunting because the bar is so high on this building, he said. "There's so much of everything to do: There's woodwork, stained glass, protective glazing, bronze doors, wood doors, and six types of stone, which all require different treatments."

But after years of expert work, St. Patrick's is just as stunning now as it was when it opened in the late 19th-century.

The stonework and marble has been repaired, the stained glass windows have been reinforced, years of dirt and soot have been removed, and an up-to-date heating and cooling system has been installed, leaving visitors with a breathtaking building that appears at once historic, but not old.

Take a closer look at the newly restored St. Patrick's Cathedral in the photos below.